1. Field of the Invention
The invention relates generally to techniques of optically displaying an image, and more particularly to improvements in techniques of moving an exit pupil of an image display device.
2. Description of the Related Art
As techniques of optically displaying an image, there are known, for example, a technique of projecting imaging light representing an image to be displayed, directly onto a viewer's retina, to thereby allow the viewer to perceive the image as a virtual image, and a technique of projecting such imaging light onto a physical display screen, to thereby allow the viewer to perceive the image as a real image.
Further, as techniques of converting light emitted from a light source into imaging light representing an image to be displayed, there are known, for example, a technique of spatially modulating surface light emitted from a light source at a time, using a spatial light modulator such as an LCD (Liquid-Crystal Display), on a per-pixel basis, to thereby generate the imaging light in the form of surface light, and a technique of converting alight beam emitted from a light source into imaging light in the form of surface light, using a scanner, wherein the light beam has been intensity-modulated on a per-pixel basis.
Japan Patent Application Publication No. hei 8-502372 discloses a head-mounted display device acting as an exemplary device for optically displaying an image. This head-mounted display device employs a technique of projecting imaging light representing an image to be displayed, directly onto a viewer's retina, to thereby allow the viewer to perceive the image as a virtual image, and a technique of converting a light beam emitted from a light source into imaging light in the form of surface light, using a scanner, wherein the light beam has been intensity-modulated on a per-pixel basis.
The disclosed head-mounted display device further employs an additional technique of detecting the position of a pupil of a viewer who attempts to view a display image, and of moving an exit pupil of the head-mounted display device to track movement of the viewer's pupil.